Automatic electrical radio broadcast and wave selector



12, 1938. w PLENSLER 2,114,068

AUTOMATIC ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR Original Filed Sept. 3, 1929 10 Sheets-Sheet l April 12, 1938. 7 A. w. PLENSLER 2,114,068

AUTOMATIC ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR 0rigina.l Filed Sept 5, 1929 10 Sheets-Sheet 2 April 1 938. A. w. PLENSLER 2,114,068

AUTCMATIC ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR Original Filed Sept. 5, 1929 10 Sheets-Sheet 3 April 12, 1938. A. w. PLENSLER 2,114,068

AUTOMATIC ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR Original Filed Sept. 3, 1929 10 Sheets-Sheet 4 April 12, 1938. A w. PLENSLER 2,114,068

AUTOMATIC ELECTRICAL RADIO BROADCAST AND'WAVE SELECTOR Original Filed Sept. 3, 1929 10 Sheets-Sheet 5 [nae/24 52" Jflermaa" ZZ/ Fla/2:197"

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' April 1938. A. w. PLENSLER 2,114,068

AUTOMATIC ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR Original Filed Sept. 3, 1929 10 Sheets-Sheet 6 April 12, 1938. A. w. PLENSLER AUTOMATIC ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR Original Filed Sept. 3, 1929 10 Sheets-Sheet '7 April 12, 1938. A. w. PLENSLER AUTOMATIC ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR Original Fil ed Sept. 3, 1929 10 Shets-Sheet 8 A ril 12, 1938. A, w, PLENSLER 2,114,068

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' I AUTOMATIO ELECTRICAL RADIO BROADCAST AND WAVE SELECTOR Original Filed Sept. 3, 1929 10 Sheets-Sheet 10 Patented Apr. 12, 1938 PATENT OFFICE AUTOMATIC ELECTRICAL RADIO BROAD- CAST AND WAVE SELECTOR Alexander W. Plensler, Chicago, Ill., assignor to Belmont m Corporation, Chicago 111.,

a corporation of Illinois Application September z. 1929, Serial No. 390,064 FEB 2 0 1940 Renewed November 17, 1937 4:: Claims. (01. zso-zo) My invention relates to means for automatically tuning radio receiving apparatus in order to select various wave lengths upon which broadcast systems are transmitting:

It is the principal purpose of this invention to provide a system whereby any one of a plurality of wave lengths or stations, as they are usually referred to, may be selected by a simple operation such as pressing a button with such a degree of accuracy as to make it unnecessary for one to operate the tuning controls in any other manner except by the use of this system.

It is also a purpose of this invention to provide a system of this character which will automatically cut oil the emanation of sound by the loud speaker of the set during the time a station'selection is being made and then will automatically connect in the loud speaker so as to cause it to become operative when theselection is completed.

My invention also contemplates certain improvements in systems of this character whereby the tuning devices may be caused to change their position by driving connection from the motor in such a manner that there is no danger of overrunning past the station which is to be selected due to the action of the motor.

Another important object of my invention is the provision of means in a system of this character whereby the receiving apparatus may be controlled from any one of ,a plurality. of different points not only as to the selection of stations but also as to the volume and as to turning the set on or oil.

In this connection, my invention contemplates the provision of means whereby a control unit situated at a remote point in respect to the radio set may be caused to remove the control setting at another point and thereafter caused to control the tuning and volume of the set from the first named remote point.

My invention contemplates also as an object the provision of a novel means of automatically tuning or wave selection which is operative to affect the tuning of the receiving set only during the time that it is changing from one wave length to another and which leaves the tuning device free for manual operation at all other times. This is particularly advantageous where it is desired only to apply the automatic control to a limited number of stations, and, when one does not wish to listen to these stations, to have the set free for ordinary tuning manually. With the present invention it is possible to tune the set manually at any time without in any way interfering with the future accuracy of operation of the automatic tuning system and without making any changes in the connection of the auto= matic system to the tuning device. nary tuning dial is used the same as it would be.

if the automatic system were not employed.

It is also a purpose of this invention to provide in a system of this character a novel means for a volume control of the receiving apparatus from. a remote point.

A further object of this invention is to provide in a system of this character means whereby the nection with the accompanying drawings where-g in the preferred form of the invention is disclosed. It is to be understood, however, that the drawings anddescription are illustrative only and are not to be taken as limiting the invention other than it is limited by the claims.

In the drawings- The ordi- Fig. 1 is a front view partly in section showing my control mechanism as applied to tuning condensers mounted in tandem upon a drive shaft;

Fig. 2 is a view showing that portion of the equipment which is to the right, of Fig. 1, so that Figs. 1 and'2 show mechanism substantially all of the unit; 4

Fig. 3 is a sectional view on the line 3-3 of Fig. 2;

Fig. 4 is a section on the line 4-4 of Fig. 2;

Fig. 5 is a section on the line 55' of Fig. 1;

Fig. 8 is a detailed section of a portion of the structure shown in Fig. 5;

Fig. '7 is a section on the line '|l of Fig. 5.

Fig. 8 is a top view of the structure shown in Fig. 7;

Fig. 9 is a vertical section taken at the right hand 'end of Fig. 2 and illustrating a portion of the control cam;

Fig. 10 is a section taken on a horizontal line.

' the set.

Fig. 14 is a view of the front panel of the radio Showing the control panel mounted thereon;

Fig. 15 is a perspective of a remotely disposed control panel which is used in conjunction with tuning apparatus;

Fig. 16 is a section on the line |8--|5 of Fig. 15;

Fig. 17 is a view taken on the line of Fig. 16 with the casing left off for the sake of clearness;

Fig. 18 is a wiring diagram showing the electrical connections for two stages of wave lengths control;

Fig. 19 is a diagram showing the wiring con nections for turning the receiving set ofl and on; and

Fig. 20 shows the wiring diagram for the volume control of the receiving apparatus.

Referring now in detail to the drawings, I show at a shaft upon which movable elements E of a plurality of condensers having stationary elements such as indicated at l are mounted. These condensers are, of course, the tuning condensers for the various stages of receiving an paratus and I show in the present instance iuur of these condensers although it is obvious that any. desired number may be employed depending upon the stages of the receiving set that it is desired to tune. i have not shown the electrical connection of these condensers to the receiving apparatus since this forms no part of this invention which is not limited to any particular receiving apparatus.

A suitable indicating dial or drum 8 is also carried by the shaft 5 and this may be illuminated from the lamp 9 in any well known manner.

The shaft :5 is rotated by means of the pulley lll fixed thereon connected by a belt drive II to a second pulley l2, there being idler pulleys l3 and it as shown in Fig. 4.- for driving the drive belt which in the present instance is shown in the form of a round cord. Pulley I2 is fixed upon shaft i5 which shaftls connected to a tuning knob 36 exteriorly of the front panel l I provided on the receiving apparatus. Shaft I5 is supported on suitable bearings as indicated at l8 and Ma and has intermediate its ends a. worm gear l9 rotatably mounted thereon which gear is provided with a clutch ring at adapted to mesh with clutch member 2| when this member 2| is moved to the left as shown in Fig. 4. The member 2| is splined to the shaft |5 by means oi. cooperating keyways 22 and 23 and a ball type key 24 which permits sliding of the sleeve 25 of clutch member 2| on shaft IS with a minimum amount of friction, but it also guarantees that member 2| will rotate with shaft l5. Suitable collars are, of course, provided to hold the gear H! in position, and this gear meshes with a worm 26 which worm is mounted on the drive shaft 21 of a small reversible type motor 28 as shown most clearly in Fig. 2.

At this point it might be well to observe that unless the clutch member 2| is in mesh with the member 20 so as to cause rotation of shaft IS with the gear I9, there is nothing to interfere with the turning of shaft l5 by means of the ordinary tuning knob I6 so as to manually tune Therefore, any time the clutch is released, the tuning device is free of all driving connections that would interfere with manual tuning.

The meanswhereby automatic tuning of the set is accomplished will now be described.

It will be noted from Figs. 3 and 4 in particular that clutch member 2| has a groove 25 with which the clutch operating arm 29 engages. This arm 28 is a movable armature secured at 30 to the frame and adapted to be moved by means of the attraction of the magnet coils 3| and 32 when they are energized. That is to say, when it is desired to throw in the clutch and drive the shaft l5 and with it through the medium of the belts and pulleys shaft 5 from the motor, the magnets 3| and 32 are energized to attract the armature 29 thus causing engagement between the members 20 and 2| of the clutch.

The arm 29 of the armature also carries 9. depending arm member 33 which arm member engages a pivoted yoke 34 by extending into the notch 35 therein. This yoke is adapted to shift contact between a pair of contacts such as indicated at 36 and 31. The center of this yoke lid is connected as indicated by the numeral 38 in circuit with some of the other apparatus as will be presently described, so that the effect of shifting from one side to the other is to alternately close points in two different circuits.

Mounted on the shaft 5 are a plurality of com units such as indicated at 39, 45, and 4|. These units are made up of pairs of sections 42 and 43 which together make up a complete circle or disc with the exception of slight apertures at 44 and 45 between the separate halves. At the center of the elements 42 and 43 they extend through a complete circle as indicated at 45 in Fig. 5 and have laterally extending flanges 41 and 48 which flanges are contacted by suitable spring contacts 49 and 50. The shaft 5, where it extends through these cam members, has an enlarged sleeve portion 5| which is flattened as indicated at 52, and insulating bushings such as shown at 53 are interspersed between the cams which are also mounted on insulating members such as indicated at 54. In this way, the cams are kept spaced and insulated from each other and also from the shaft. This construction it will be noted also insulates section 42 of the cams from section 43.

Now the insulating pieces 54 and 53 are clamped in position on the member 5| by suitable nuts such-as shown at 55 and 55 and this clamping is preferably made only so tight as to normally prevent turning of the cam members on the shaft 5|. However, due to the frictional gripping between the insulating pieces 53 and 54, it is an easy matter to tum the shaft 5 and the sleeve 5| while holding any one of the cam members 39, 40, or 4| against rotation.

The cam members can thus be adjusted circumferentially around the shaft 5 to change their relativeposition with respect to the movable blades 8 of the tuning condensers. The purpose of this is to permit adjustment of these cam members which control. as will be brought out presently, the amount of turning which will be given to the tuning condensers each timev the clutch members 20 and 2| are brought together and the motor started.

Figs. 5 and 6 show means whereby the cam members 42 and 43 are brought into action to control the termination of the turning of the movable condenser elements at the proper position for the station to be selected. An electro magnet consisting of the two coils 51 and 58 is mounted below each of the cam members 39, 40, 4|, etc., and in position to be attracted by these magnets there is situated a series of armatures such as 59, 60, and 5|. These armatures, as indicated in Fig. 5, have at their free ends a contacting portion 62 which contacting portion is adapted when the armature is attracted by the electro-magnets to engage the outer surface of one of the cam members depending upon which armature, is attracted by its corresponding elec- 'tro-magnet.

Now at the same time this armature is attracted, the second contact member 53 carried by the armature 59 and insulated therefrom is brought forward to contact with a contacting pin 64 which pin extends through-the core of coil 51. The contact between the member 53 and pin 64 is adapted to close another point in the energizing circuit as will be brought out presently in connection with the wiring diagram of the system.

Referring now to Fig. 18, the wiring connections for a pair of cam elements such as 39 and 40 is shown it being understood, of course, that the remainder of the cam elements are wired in a like manner to the two shown. In this diagram, a source of current as indicated at 64' is connected by means of one lead toone terminal of the reversible split field motor 23. Another terminal of this motor is connected by means of the lead 66 to one of the cam sections 42 of each of the cam members 39 and these sections being connected in parallel as shown. The other terminal is connected by means of a lead 61 to the sections 43 of the cam members 39 and 40.

The armatures 59 are connected as by leads 68 and 69 to the positive side of the source of current as illustrated in Fig. 18. The electro-magnets 51 including also the extra coil 53 which for the sake of convenience in the wire diagram has been shown as a single magnet have one terminal connected by means of the lead II to the positive side of the source of current. The other terminals of these electro-magnets are connected through suitable push buttons, which will be described later, indicated at 12 and I3 to the negative side ill of the source of current.

Connected to contact 36 are the conductors 14' tons 12 and 13. The yoke 34 has been shown diagrammatically in connection with the armature 29 and the electro-magnetic coils 3| and 32, with the electro-magnet referred to in the diagram sketch of Fig. 18 as 3| and the armature as a single movable armature 34 having a pair of contacts with which the terminals 33 and 31 engage, this armature being connected by means of conductor 38 with the terminal 19 of the source of current. Electro-magnet 3| is energized by means of leads l1 and I3 connected across the leads G6 and 61 of the motor so that any time the motor is energized this electro-magnet will also be energized. The terminal 31 is connected by means of a lead 13 to one side of the loud speaker indicated at 30, the other side thereof being connected by means of the lead 3| to one terminal of the source of current 54'.

Now the operation of the system to rotate the tuning device is accomplished as follows;

Assuming that the station corresponding to the push button 12 is to be selected, push button 12 is depressed to close a circuit extending from the source of current through lead ll, coil of magnet 51, contacts of push button 12 to terminal 10 of the source of current. This energizes electro-magnet 51 associated with button 12, and this magnet in turn attracts armature 59 associated therewith which armature 59 contacts with segment 43 of cam member 39.

At the same time contact 33 engages the end of the pin 64 and completes a holding circuit for the previously energized magnet 51 over the following path:

Positive side of source of current, conductor H, coil of magnet 51, contact 63, pin 64, conductor 14, terminal 36 (electro-magnet 3| was energized by the depression of push button 12 over a path which will be presently described, so armature 34 is now in contact with terminal 36) armature 34, and conductor 38 to negative side of source of current at '10. This completed circuit will, of course, hold the electro-magnet 51 energized independently of the push button I! which is only momentarily depressed. Contacting of armature 59 with segment 43 completes an energizing circuit for the motor by connecting lead 51 thereof through the segment 43, armature 59, and switch a. to the positive side of source of current 64'.

The motor is energized in this fashion and when so energized rotates the shaft 5 carrying the cams 39 and 40 in a clockwise direction. Armature 59, of course, remains in contact with the segment 43 during this operation. The energizetion of the electro-magnet 3| has, of course,

thrown the clutch member 2| into engagement withthe clutch member 20, so that as the motor rotates it drives shaft 5 through the medium of shaft l5 and the associated pulleys and belt connection.

As another result of the energization of electro-magnet 3|, the circuit is broken at 31 for the loud speaker 80, so that the loud speaker is rendered inoperative during the tuning operation.

The motor is energized until such time as the contacting portion 62 of armature 59 falls into the depression 44 between segments 42 and 43 at which time these segments are electrically connected by means of this contacting portion 62 to short circuit the motor leads 98 and 61 and thereby the electro-magnet 3|. The immediate result of this short circuit is to release the armature 34 which will fall back due to its being a spring armature to open the clutch and thus stop the rotation of shaft 5 suddenly. Armature 34 4 in falling back also breaks the energizing circuit for electro-magnet 5'! at 36 which permits armature 59 to fall back and restore the circuit to normal with the motor deenergized due to the fact that positive side of battery 64 is now disconnected from either lead 66 or 61. At the same time the falling back of armature 34 closes at 31 the energizing circuit for the loud speaker 30 to cause the loud speaker to again be put in operation.

As this adjustment of the turning of the shaft 5 by stopping the cams such as 39 and 40 on a definite point may be made quite critical, tuning to the desired station is made very accurate so that no further fine tuning is necessary after the station has been selected by the automatic device.

The operation of push button 13 will, of course. have the same effect to energize the associated electro-magnet 51 and attract the associated armature 59, but, owing to the different setting of the cam 40 for a different wave length, the armature 59 associated with button 13 will contact as shown in Fig. 18 with segment .42 of cam-43. This will result in energization of the motor 23 by connecting negative battery to lead 56, so that in this case the motor will be rotated in a counterclockwise direction, and the operation repeated with this variation in the same manner as has been previously described.

In this manner, it is possible to select as many stations as there are provided cam members suchfor a different station the switch a which is normally closed is used. The button it corresponding to the station to he changed is pressed. This operates the selecting mechanism to bring the cam corresponding to that button into posttion to bring part 52 into gap Q4. Elwitch a located on the panel is then opened and button it is again depressed. This energizes coil i and attracts arm 59. Coil ii! is locked energized in a novel manner. The attraction of armature 59 into gap it causes it to contact with the end of the core of magnet 51. The energizing circuit for this magnet may then be traced over the following path: positive lead Ii, coil of magnet, contact pin E l, core of magnet, armature 59, cam 3%, leads it and 3'! of motor 28, winding of motor 28, and lead 65 to negative battery at it. Leads 66 and ti of the motor field being short circuited by cam 39, the motor remains stationmy and magnet Si is not energized.

The manual tuning knob Hi can now be turned and part will hold cam 39 against rotation While the shaft b is turning. The shaft 5 is turned in this fashion until the desired station or wave length is tuned in. When this is accomplished, switch a is moved to its original position which deenergizes coil 51, and restores the system to normal ready to use. In this fashion the wavelength for all of the push buttons and their associated cams may be varied at will without the necessity of getting inside the selector or manually holding anything.

The electrical characteristics of this system are such that it is practically fool proof. For instance, if two buttons such as I2 and 13 are depressed at the same time, no harm can result. If their corresponding arms 59 are opposite on cam sections 42, the shaft will be turned until the first gap 44 of the two is reached when the motor will be deenergized; and, if one arm is opposite section 42 and the other opposite 43, then nothing will happen when both buttons are depressed, as the motor leads 66 and 61 will be connected to each other thru arms 59 and conductor 68.

Keys 12 and 13 may be located at any desired point, either at the receiving set or remote therefrom. I also provide means whereby duplicate sets of such keys may be arranged at different points so that the control of station selection may be had at several points remote from or at thereceiving apparatus. The wiring diagram by means of which this is accomplished is, of course, the same as shown in Fig. 18 with the exception that instead of a single button 12 parallel leads may be run to additional buttons such as indicated at 12' in Fig. 18 so that the circuit energizing the electro-magnets 51 may be completed at any point where a button such as 12 or I2 is located. It is to be understood, of course, that there are as many buttons provided at each point as there are stations to be selected.

'of conducting material.

The arrangement or this duplication of selecting buttons is illustrated in Figs. 9 to 15 and will now be described.

In Fig. 14, there is shown the front panel I! of a radio receiving apparatus having thereon a button panel as indicated at $3, this panel I], of course,having the tuning handle I8 thereon for tuning independently of the automatic wave selecting device and having an aperture as at 84 through which the dial or drum 8 is visible. A suitable volume control knob is indicated at 85 which knob will also be described in connection with the volume control. The panel 83 is shown in vertical section in the end view, Fig. 9,

and therein view, Fig. 11, while Fig. 10 is a horizontal section thereof.

The construction of this panel is as follows: Mounted on the back of the panel H are a plurality of insulating frame members 88, 81. and a grounded aluminum bracket 88, the members 38 and 81' having thereon vertical rows of terminal screws such as 88 and 90 which terminal screws extend through and have a i'ree end spaced from the front panel 83. member 88 there are provided a. plurality of spring plates 9| which are connected at their center as indicated at 92 to one side of the source of current as for instance to the side III as indicated in Fig. 18. The panel 83 is, of course, The spring plates 9| are apertured to receive clips 93 which are adapted to snap in and out of an aperture-readily by means of the spring fingers ill and 95 thereon and the clips 93 carry suitable indicating plates Q6 preferably of insulating material and preferably translucent which plates carry thereon the call letters of the station which is to be selected by the depression of the spring plate associated therewith to contact with the associated terminal 89 or 90. A suitable lamp as indicated at 91 in Fig. 2 and Fig. 9 is used to illuminate the case at the receiving apparatus. For a duplicate set of keys reference is made to the control box shown at 98 in Fig. which has mounted therein in the same manner as the mounting on panel 83 a duplicate series of keys or buttons such as shown at 93, the wiring connections being made through the cable 99 from this key box 98. Cable 99 may be run from a set to any point desired as for instance to any other room in a. house, and the control box 98 being small may be located on On the a table or desk or chair or placed upon a flexible Y cable such as 99 so as to be moved about from place to place. The practice of having a central radio receiving set and loud speakers throughout the house is becoming very common, and, by the set. I have provided a simple device whereby this may be accomplished with a small amount of equipment at the receiving apparatus and the addition of the volume control dial and shut oil button at each control point.

In Figs. 5, 7, and 8 of the drawings the necessary equipment at the receiving apparatus is shown and in Figs. 19 and 20 the wiring connec- .tions for turning the set on or oil! the controlling the volume are shown.

In regard to the volume control, referring now to Fig. 20, I provide means whereby suitable resistance such as I and IN located one at each control point and are so connected that they may be shunted across a secondary I02 of one of the stages as indicated at I03 in the audio frequency amplification in the receiving apparatus in this way to control the amount of amplification which will be made of the signals received. These resistors I00 and IN may, of course, be inserted in other points of the circuit for volume control wherever desired, this instance merely being given as an example of how volume control may be connected to the receiving apparatus. In- Fig. 20 the movable contacts I04 and I05 of resistances 500 and IM are connected in parallel by means of lead I08 to one terminal of the secondary I02. The other terminal of the secondary I02 is connected by means of a lead M1 to an armature B09 which armature is controlled by a pair of eiectro-magnets I09 and H0 so that when magnet I09 for instance is energized armature I09 will be moved into contact with spring contact III, and, when magnetIIO is energized, armature I08 will be disconnected from spring contact III and connected to spring contact II2, these contacts III and H2 being connected to one terminal of the resistances I00 and IN, respectively.

Now by turning the volume control knob 09 at the receiving apparatus or 80 at the remote con- .trol point into one limiting position, that is to the position where the secondary I02 is comresponding to no volume emanating from the receiving apparatus, an insulated member II3 carried by the shaft of the .control knob is brought into position to press a spring contact II4 into engagement with contact II! which'is connected "to one terminal of the source of current 64'.

When this occurs, magnet I09 is energized over a path extending from the positive side of a source them at the same time so that either resistor IN or I00 is shunted across the secondary I02 at all times. As shown in Figs. 16 and 17, the elements I I3 and I I4 consist of cam portions mounted upon the rotating element I04 of the resistors in such position as to move the element II4 upwardly to contact with the element 5 when the movable member I04. reaches its limiting position-in one direction. T

In addition to the volume control just described, thevolume control knobs 33 and 00' have centrally mounted therein pins 0 and 0' which may be depressed to shut oi! the receiving apparatus whenever it is desired. The mechanism by which this is accomplished is shown more clearly in Fig. 18 wherein the pin H3 is shown as mounted on a contact making pin III which pin is adapted when depressed to make contact with the stationary contact I I0 and complete a circuit for opening a switch to cut off the supply of energy to the receiving apparatus.

In Fig. 19 the wiring diagram for this connection is shown, the contacts I" and H8 being shown in duplicate, that is, one for the volume control at the receiving apparatus and one for the volume control in the control box 99. The

power line is shown at i1I9 as being connected to the filaments of tubes i120 of the receiving apparatus and passing therethrough to contact I2I which is adapted to be connected by a bridging element 222 to a second spring contact I23 to complete circuit over a conductor I24 to the other side of the source of current supply for the tubes. The bridging contact I22 is carried on a pivoted shaft I25 as shown in Figs. 12,,13, and 19 .which shaft carries the ratchet wheel I26.

the spring I3I so that its normal position is that shown in Fig. 12. Movable core I carries an arm 2 which has a spring finger I33 thereon engaging with the teeth of the ratchet wheel I29. Thus it will be seen that every time a button H5 or 9 is depressed it closes one pair of the contacts II! or III to energize coil I29 which attracts the core I30 and causes the spring finger I33 to move the ratchet wheel and the associated bridging contact one step ina clockwise direction. In this way the bridging contact can be moved into and out of position engaging with the contacts I2I and I23 to make and break the circuit which energizes the. receiving apparatus. With the above mechanism it is therefore possible to tune the receiving apparatus from a remote point so as to cause it to automatically select any one of a plurality of stations which are represented on the control panel and also to turnthe set on or oil from any one of a plurality of points and control the volume or the set from such points. All this is done with a. minimum amount of equipment in the remote control box which can be made very small, its dimensions in fact being substantially those of the drawing in Fig. 15 so that this remote control box or a plurality oi them may be placed at various places throughout a home.

A distinctly advantageous feature of this system lies in the fact that during the automatic tuning the speaker is shut off so that no unpleasant howls or noises are produced by tuning while the speaker is on. Where a plurality of speakers are used, it is obvious, of course, that the same apparatus which shifts control of the volume from one of the volume control elements to the other may also shift the speaker circuit connections from one speaker to another at the same time. This control in no way interferes with the ways disconnected while the speaker is on cre ates no objectionable static or noises in the receivina' 80pm. Having thus described my invention what I M ing in combination a rotatable t claim as new and desire to secure by Letters Patent is:

1. In a radio tuner, a rotary tuning shaft, insulating means on said shaft, a selector unit supported by said insulating means comprising a pair of complementary conducting segments provirled with locking means arranged in a precie termined radial position, contact means for engagement with a segment to cause rotary move ment of the shaft, with said contact means acting to engage said locking means to stop the shaft and the selector unit.

2. it. control system for a radio receiver in eluding a driving motor, a selector unit compris ing a pair of separated members, contact for engaging one of members to cause rota tion lay said driving motor in one direction. or other depending upon the member rotation continuing to a predetermined one position of said selector unit s .o comeans to engage both members simultc ieomly to stop such rotation at such predictor ruined point.

3. In a tuning device troller connected to a sh n3 spaced conductors root e plurality of contact members relative to the conductors, electr'c nectecl the conductors, contiguous eat conductors contact members may he projected. cess to simultanecnsy ctrciuts.

pair of spaced conductors on said and rotatable therewith, "on can having two spaced apart te cairl conductors positioned another in a manner provide 2. ttion one adjacent tor-min other, contact means for 133 to rotation of s o 1 r ge said acjacent terminal. a p e 1&6 rrcinecl pcsi on oi saitl. shaft EUR stopping rotation or. said sirt.

ii. control apparatus for an adjustr-i ole ftQViCE, said apparatus including a shaft connected with said aotiustalole device for moving the latter, :2 rotor on shaft including pair of conductin segments insulated from one another, each seg merit having a terminal portion in a coi'rcspoml ing position thereon, power means for thriving said shaft, and means for discontinuing the driv ing of saicl shaft, including a contact member for bridging said terminal portions.

ii. Control apparatus for an adjustable device, said apparatus including a shaft connected with said adjustable device for moving the latter, a

pair of spaced members on said shaft, each having a terminal portion thereon correspondingly positioned with respect to one another and im sulated from one another, power means for driving said shaft, an electrical circuit including said power means and saitl terminal portions, and

terraces actuating said spring arm to cause the projection to press against a conducting segment to complete an electric circuit causing said shaft to rotate and retain said arm in engagement therewith until said projection. is in registry 5 with said recess, with the spring pressure be- I tween the retained spring arm and cam unit causing said projection to spring into said recess whereby to simultaneously engage each conducting segment mechanically and electrically to stop the rotation of said shaft.

it tuning system for a radio receiver including a rotary shaft, a reversible motor for driving said shaft, 9. control unit on said shaft and normally rotatable therewith, said control urrit including a pair of separated conducting segm nts, a contact for engaging one segment or the other to complete a circuit through the engaged segment for causing rotation of the motor in one o... ection or the other depending upon the segment engaged said rotation continuing to a predetermined point to permit saicl contact to en.-

both segments to form short circuit to rencier the motor inoperative to rotate i). In a control for a radio receiver, a. condenser, a reversible motor to rotate SI: clenser, a station selecting member rota-t sair'i oonrlenser including a pair of spaced clrcumierentially to for nrough that segment, the segrc 1mg the direction rotation. oi t sol-cl segment rotatable to to try with the brush 'tvhereh "es hot'n segments simultaneous cl shortecircuit the circuits throng i to stop the motor.

In selective tuning device tus, a rotary shaft, a of court .ct on said shaft insulates from on. insulated from shaft, clectricaii,

power means driving saicl sh 'e or counterclockwise, contact mean" ior c gagement with one segment or the otl: r to mate the power means to cause rotation shaft clockwise or counterclockwise depem upon the segment engaged, each. of said merits having a terminal portion at each en: provide a terminal portion of one segme cent a terminal portion of the other, and use. .1 responsive to the simultaneous engagement oi; two adjacent terminal portions by said contact means to cause the stopping of said rotary shaft. 11. In a tuning system for radio receiving r3c-- vices, a tuning device, a rotary shaft for oper-- ating said tuning device, a reversible motor ior driving said shaft, and control means for moving said tuning device'to a predetermined point and stopping it there comprising a pair of complementary conducting segments encircling said shaft each connected to the energizing circuit of the motor so that completion of the motor circult through one segment causes rotation in one direction, and completion of the motor circuit through the other segment causes rotation in the other direction, control means including a contact element cooperating with said segments to energize said motor and turn the shaftto bring the contact element into engagement with both said segments, and means rendered operative by the connection or both said segments to deenergize said motor and stop said shaft.

12. Int. tuning system for radio receiving sys- 75 terns, a tuning device, power means to actuate said tuning device, individual selecting means for different settings of said tuning device operable to cause said powermeans to act ate the tuning device and adjust it to the sele ted setting, said individual selecting means each including a member connected to said tuning device for moving it, a pair of complementary .conducting segments movable by said member, a contact element normally out of contact with either segment, control means for causing said contact to engage one of said segments, a clutch device actuated by engagement of one segment with said contact element to cause movement of said member by said power means to bring the contact element to a point where it contacts both of said segments, and connections from the contact element and said segments to the clutch device releasing the clutch device when the contact element engages both segments.

13. In a control for a radio receiver driving means therefor, a rotary shaft, a station selecting member on said shaft rotatable by said driving means, said member including a pair of conducting segments spaced circumferentially to form a gap, means for selectively connecting said driving means to said rotary shaft, a brush adapted to engage one of said segments to complete a circuit for energizing said connecting means to connect said shaft and driving means to cause rotation of said station selecting member, an electro-magnet for attracting said brush to said segment, depressible switch means momentarily depressible to complete a circuit through said electromagnet to energize the same, and means for holding said brush in engagement with said conducting segment for a predetermined rotary interval of travel after release of said depressible switch means. I l

14. In the device of claim 13, said brush including a supplemental contact portion movable therewith and in electrical connection therewith, with said holding means for said brush including a circuit having said supplemental contact portion therein and a stationary contact in electrical connection with said electro-magnet for electrical engagement with said supplemental contact portion.

15. Control apparatus for an adjustable device, said apparatus including a shaft connected with said adjustable device for moving the latter, a plurality of rotors on said shaft, each including a pair of complementary conducting segments insulated from one another, insulating means for mounting said rotors on said shaft and insulating them therefrom, each of said segments having a lateral flange over a portion of the periph- -ery thereof and a terminal portion at each end of said flange with said segments positioned ina manner to provide a terminal portion on the flange of one segment adjacent a terminal portion on the other segment, power means for driving said shaft, and contact means for bridging a pair of adjacent corresponding terminal portions.

16. A control device for controllable apparatus including a rotary shaft, and a selector unit on said shaft acting to control the rotation of said shaft, said unit comprising a pair' of conducting segments insulated from one another, with each segment comprising a disc-like body portion and a peripheral lateral flange extending over less than 180 of the periphery of the body portion, each flange formed to provide a shoulder at each endthereof with said segments positioned with respect to one another sothat the flanges are substantially coextensive and adjacent shoulders of the flanges are separated to define a gap therebetween, contact means for said selector unit acting to complete an actuating circuit for said rotary shaft and the unit thereon, said contact means having a substantially wedge-shaped projection' thereon for initially engaging a conducting segment to cause rotation thereof toa point at which said projection enters one of said gaps for electrical engagement of each segment and mechanical locking of the selector unit.

17. In a control device for controllable apparatus, a rotary shaft, electrically controlled power means for driving said shaft, a selector unit on said shaft for controlling the rotary movement thereof, said selector unit comprising a pair of adjacent conducting segments insulated from one another and each having an engaging edge over less than 180 of the outside thereof, with said segments having a gap common to adjacent ends of the engaging edges, a movable element for contact with an engaging edge for actuation of the power means to rotate said shaft, and means responsive to the simultaneous contact of said movable element with. two engaging edges at a gap to stop said shaft.

18. An arrangement for controlling the angular movement of a shaft including driving means for the shaft, control units on said shaft acthig to stop the angular movement of the shaft at a predetermined point, each of said control units in .cluding a pair of complementary segments with an engaging edge approximately 180 in length on each segment, and said engaging edges oppositely disposed and formed in a manner to provide a recess common to contiguous ends of said engaging edges, a contact element for engagement with an engaging edge of a control unit segment to close an electric circuit actuating said driving means, with said contact element adapted to enter said recess of said control unit to render said driving means inoperative to move said shaft.

19. A control system for a radio receiver including a driving motor, a rotary shaft driven by said motor, a selector unit on said shaft comprising a pair of complementary conducting members each having an engaging surface over approximately one-half the edge portion thereof with said engaging surfaces oppositely disposed with respect to one another and of such shape as to provide a recess at adjacent ends of the oppositely disposed surfaces, a contact element having a wedge-shaped projection upon one end thereof for engaging one surface or the other to energize the motor to cause rotation of said selector unit to a point at which said wedgeshaped projection enters said recess to electrically connect said conducting members to stop said motor and mechanically stop rotation of said selector unit. I

20. An arrangement for controlling the angular movement of a shaft comprising means for angularly moving said shaft, a member arranged maintain the latter in its operated position fol- 8B pro said operating 1 upon the release of said manually operable switch.

22, iin arrangement for controlling the angular movement of a shaft comprising means for angulariy moving said shalt, a member arranged for movement with said shaft, an element piv otally mounted for movement away from member and for movement into engagement with said member to stop said shaft at a predeter ruined point, operating means for movlng'saiii element into engagement with said member, an operating circuit for said a push-button switch for controlling the operation of oper=- ating circuit a normally open switch con necterl in parallel with said. push-button switch arrange-cl to be closed upon the operation of means whereby it will maintain the operating circuit for scold operating upon the release of said pusln button suit 23. a control for a receiver, electric ion selecting member rotat said driving means including pair conducting segments circuznzferentiallv iorrn with each of segments comes to said driving means, a adapted to one of said. segments to complete the eruer circ through ttiat to cause rotnti M tending means including; a contact member having a substantially wedge-shaped projection at one end, an electro-magnet for attracting sold contact member to cause the projection to engage the selector rotor surface, a switch for-momentary closing to energize said magnet, a stationary contact in electrical connection with the energizing circuit for said magnet, and: a supplemental contact portion on said contact member acting upon movement of said contact member for engagement with said stationary contact to maintain said magnet energized after release or the switch means. I

25. A control device for controllable apparatus including a rotary shaft, a selector rotor on said. shaft including a pair of conducting segments separated peripherally at two oppositely disposed points on the surface of said rotor, driving means for saidshaft, means for extending a circuit through a selector rotor segment to energize the driving means, said circuit extending means inof said manually operable.

eluding a movable contact member, an electromagnet for attracting said contact member to cause it to engage a rotor segment, a switch for momentary closing to energize said magnet, a stationary contact member in the energizing circuit for said magnet, and a supplemental contact portion on said movable contact member for engagement with said. stationary contact member to maintain said magnet energized after release of said switch means to continue energization of said driving means for rotation of the rotor until said movable contact member engages both of said segments at one of said separated peripheral points and simultaneously therewith acts to rencler said if "ll'lg means inoperative.

ntomatic tuning system for radio receiving ap aratus including a manually operable tuning element, a motor for adjusting said tuning element, selective control devices for stopping said means at any one of a plurality of positions oepending upon the control device operated, and electric means for holding any one of selective control devices while the tuning ele-,

ment is manually operated whereby the-position of tuning; element relative to the held select ingdevice may be varied at will.

27. an automatic tuning system for radio recalving apparatus including a manually operable element, a motor for adjusting said timin element, selective control devices for stop plug said tuning means any one of a plurality of positions depending upon the control device operated, and. electric means for holding any one of said 5 lective control devices while the tuning element is manually operated whereby the position of the tuning element relative to the held selection; device may be varied at will, said. holdincluding means rendering said motor i l. control device r controllable apparatus, manually rotatable shaft, a "BEES irictlona'ily mounted on rotatable therewith but t 0 turn tnerein when held, 1 shalt, electrical means i /int; means from the u. is Wter i positions of said control members, and electrically operated means or incision; any one oi said cont 11 members against rotation, whereby to permit manual turning of sold halt independently oi; held control In a system of the character described, a control device for changing the characteristics of an electrical circuit, said device having a movable element, a manually rotatable shaft for moving said element, a series of cam members frictionally mounted on said shaft and normally rotatable therewith but permitting said shaft to turn therein when held, a. motor connected to said shaft, clectro-magnetic means to release the motor from the shaft at predetermined positions of said cam members, and eiectro-magnetic means for holding any one of said cam members whereby to permit manual turning of said shaft independently of said held cam member.

30. A radio tuning device comprising a cam mounted on a rotary tuning shaft, said cam having a recess in a predetermined angular position of said cam corresponding to a selected broadcast station, a movable member having a projection for engagement with said recess for looking said disc against rotary movement, electromagnetic means i'or drawing said projection into said recess and holding the same therein, and

2,114,068 manual means for rotating said shaft while holding said cam to change the angular relation between the cam and the shaft. I

31. In a radio tuner, a rotary tuning shaft, insulating means on said shaft, a selector unit supported by said insulating means comprising a pair of complementary conducting segments provided with locking means arranged in a predetermined radial position, a combination contact and stopping member for selective engagement with a segment to cause rotation of the shaft to a point at which said member engages said locking means to stop said shaft and unit, and means for bolding the combination member engaged with said locking means to hold said unit stationary while manually rotating said shaft.

32. Ina tuning system for a radio receiver including in combination an electric driving motor,

a rotor driven by said motor, said rotor including a pair of complementary discs insulated from one another, a contact for engagement initially with one of said-discs to extend a circuit I through said disc to said motor to cause said motor to rotate to drive said rotor, means including a push-button remote from said radio receiver for extending a circuit through said contact, with said rotor rotatable by said motor to an angular position permitting engagement of. both discs simultaneously by said contact to form a shortcircuit across circuits including both said discs to cause stoppage of said rotorand render said motor inoperative to drive said rotor.

33. A tuning control system for a radio receiver including in combination, an electric driving motor, a rotary selector unit including a pair of complementary conducting members, a movable contact element, depressible means remote from said radio receiver to cause said contact to engage a conducting member upon the depressing of such means to energize said motor to rotate said selector unit to a predetermined position at which said contact element engages both discs, said contact element causing a short circuit across circuits through each of said conducting members at such predetermined position to render said motor inoperative and stop said selector unit.

34. A control system for controllable apparatus including in combination a rotary shaft, means for rotating said shaft, a control unit supported on said shaft including a pair of spaced conductors insulated from one another and with the contiguous ends of such conductors forming a recess, an electric circuit connected to each conductor, a selector member for said control unit having a projecting portion thereon, means to move said selector member into engagement with one conductor or the other of the control unit to complete an electric circuit through the conductorengaged to cause rotation of the rotary shaft by the rotating means to an angular position at which the projecting portion of the selector member projects into a recess of said control unit, with said projecting portion in the recess acting to stop the rotation of the control unit at that angular position.

35. In a tuning device for a radio set, frequency changing means actuated by a rotary shaft, means for rotating said shaft, a pair of spaced conductors supported on said shaft and movable therewith having contiguous ends forming a stop gap, stationary contact means for electrical connection with each conductor, movable contact means for engagement with one or the other of said conductors to extend a circuit therethrough and initiate rotation of said shaft to a point where said movable contact means is moved into a stop gap at contiguous ends of said conductors to firmly seat therein and effect the stopping of rotation of said shaft and control unit.

36. An arrangement for controlling the angular movement of a shaft comprising a plurality of control members carried on said shaft, with each of said members having a periphery thereon, power means for driving said shaft in a clockwise and a counterclockwise direction, an element corresponding to each control member mounted for movement into engagement with a corresponding member with the periphery of said member defining the limits of initial movement of said-element, each of said control members hav-.

ing a pair of oppositely disposed recesses in the periphery thereof and two oppositely disposed peripheral portions intermediate the recesses, with one'of said peripheral portions determining clockwise driving by said power means upon engagement of an element therewith, and the other peripheral portion determining counterclockwise driving by said power means upon such engagement, a manually operable switch for closing a circuit to initiate movement of said shaft to a predetermined angular position, a circuit controlled by said switch having means therein actuated by the closing of said switch to cause pivotal movement of one of said elements until said element is in engagement with the periphery of the corresponding control member, and switch means in said circuit adapted to open when said pivotal element drops into one of said two peripheral recesses of the control member after angular movement of said shaft with the pivotal element in engagement with such control member thereon, with said rotary shaft stopping upon opening of said switch means.

37. A tuning device for a radio receiver including in combination a plurality of rotatively supported control units, a double field motor for driving said units, each of said control units including a pair of segmental conductors insulated from each other with contiguous ends, of said conductors forming a recess and each conductor electrically connected to a separate motor field so that both conductors are in normally open motor circuits, a plurality of selector contacts with a contact corresponding to each control unit, and each contact having a projection thereon, with said selector contacts adapted to be selectively moved into engagement with a conductor of the control unit corresponding to the contact selected to close a circuit through the motor field connected to the conductor to cause said motor to rotate in a directionto move a recess in said control unit into registry with the projection on the selected contact, with said projection being urged into the recess at that position to cause the control unit and the motor to stop. i

38. In a selective tuning device for radio apparatus, movable tuning means, a pair of comments for causing said power means to move said segments in a direction to bring adjacent end portions of said segments beneath said selector member, actuating means connected into said electrical means for moving said selector member into engagement with a segment, and means operative when said selector member is in seated engagement with adjacent end portions of the pair of conducting segments to stop said conducting segments and said power means.

39. A tuning device for a radio receiver including in combination, a rotary shaft, a double field motor for driving said shaft, a plurality of control rotors, each having two substantially complementary peripheral portions together extending over substantially a 360periphera1 path, a pair of oppositely disposed recesses in said peripheral path, a movable selector finger for each rotor having an end portion adapted to engage a peripheral edge of one rotor portion or the other to determine the direction of rotation of the motor, magnet means for moving said finger into engagement with a peripheral portion, a momentarily depressible switch for closing an energizing circuit for the magnet means, means for completing a motor circuit through one field or the other upon said engagement, and electrical holding means for maintaining said finger on said peripheral edge after release of the switch until the end portion of said finger is projected into a peripheral recess to effect stopping of said rotor and said motor. I

40. A tuning system for a radio receiver including in combination, a tuning element, means for varying the tuned position of said element including a rotor having a pair of conducting segments insulatedfrom one another, a contact for engagement with one segment or the other depending upon the angular position of the rotor and the segment engaged determining the direction of rotation of said rotor, power means for rotating said rotor having electrical connection therewith, means for energizing said contact to start rotation of said rotor, with said contact acting to cause the stopping of the rotation of said rotor when said contact engages both segments simultaneously.

41. In atuning device for a radio receiver, a. rotary shaft,'a plurality of control units on said shaft, each unit including a pair of conductin segments having their engageable edges together extending through substantially 360", an insulating portion between said segments, with said unit having a recess at each of two-oppositely disposed points on the periphery thereof at the insulating portion, a reversible motor including a pair of fields for driving said rotary shaft, with one of said fields adapted for energization for clockwise rotation of the motor and the other field for counterclockwise, electrical connecting means for each of said segments to a corresponding mo tor field, a movable contact for engagement with one segment or the other to complete a circuit through the field of the motor connected to that segment to cause rotation of the motor and shaft in a corresponding direction depending .upon which segment is engaged, with said unit rotating with said shaft until the end of the contact seats in a recess in the unit to effect stoppage of the motor.

42. A control device for controllable apparatus including a rotary shaft, power means for rotating said shaft, a plurality of rotors on said shaft normally frictionally retained against rotation thereon, each of said rotors having a pair of oppositely disposed recesses in the periphery thereof, a plurality of selector fingers corresponding to said plurality of rotors with each finger having a' projection at one end thereof, electromagnetic means for selectively pivoting a finger into engagement with a corresponding rotor and maintaining said finger in engagement while said rotor is rotated by said power means to an angular position with the finger projection in a peripheral recess of said rotor, a switch for actuation to initially energize the electromagnetic means and acting when closed to maintain said electromagnetic means energized to hold the finger projection in said recess and retain the rotor against movement while manually rotating the rotary shaft to change the relative angular position between said shaft and said motor, said power means during said manual rotation being inoperative to rotate the shaft.

ALEXANDER W. PLENSLER. 

